This is not exactly quality woodworking. I need to replace the inadequate foundation for the microwave in our RV with a wooden platform. The microwave will be held in place with a couple of angle irons screwed to the bottom of the microwave cabinet, folding over the edge of the wooden platform, and screwed into the edge of the wood (probably #8 or #10 sheet metal screws). The simplest material to use will be 3/4" construction grade plywood. What is the collective experience with that? Will I be splitting the plywood?
Fastening screws without drilling holes very likely will split the plywood.
I've done that by drilling holes in the plywood, almost clearance holes, then injecting some glue then fastening the screws. This worked well but I don't know if I'd want to hang from the screws over the edge of a cliff.
I've also clamped the wood tightly on either side as the screw was fastened - this allows the threads to cut deform and cut into the wood without pushing the plies apart.
There are also fasteners that work well holding things tightly to the edges of plywood or MDF - some use cylinders or other inserts and are threaded for machine screws, not wood screws. Much of the cheap fake wood furniture that requires home assembly comes with these now. I can't remember the name of the fasteners right now.
Maybe try some methods on scrap plywood and see what works best for your situation. Baltic birch plywood will probably fare better than the utility stuff from the big stores.
Same as John. I`ve been putting screws into ply for years by drilling a hole first, put a little glue in, then put the screw in, and then get a locking grip vise grip C clamp with the swivel pads on the ends and clamp it right over the hole and put in the screw.Good luck Larry
I will add that I have seen screws made for MDF. They appeared to have very sharp, somewhat exaggerated threads. And, I like Kreg screws. They are self drilling and have thin shanks and sharp threads. They are my go to screws for lots of things now. I would try them on some scraps and I might drill a hole first.
I've found the best type for edges in sheetgoods, plywood, mdf, or particle board, is 7mm confirmat but it really must be used with the proper drill to ensure that the profile of the hole is "just right". I use a special drill bit which does the job in a single shot but I guess it could be accomplished in multiple steps using regular bits.